This invention relates generally to systems for handling groups of articles suitably segregated into groups of a size adapted to fill one of a continuous line of packing cases being fed continuously through a discharge station associated with a rotary packer. Each article group moves around a circular orbit from an infeed station to the discharge station where each group is drop packed into an upwardly open case. More particularly, this invention relates to the means for feeding the cases seriatim through the discharge station so that each case is sequentially accelerated and decelerated in a manner that matches the horizontal velocity component of the orbiting article group in an associated grid with the speed of the case to be filled.
The case feed conveyor system to be described herein is especially adapted for use with a continuous motion bottle packer of the type shown in a pending application entitled "Continuous Motion Bottle Packer", Ser. No. 425,104, filed Sept. 27, 1982 and assigned to the assignee herein since issued under U.S. Pat. No. 4,457,121, July 3, 1984. This pending application shows a plurality of grids provided in a rotary structure which is adpated to move each grid in turn through an article infeed station where groups of articles are fed into one of these grids without interrupting either the forward speed of the article group or that of the grid itself. The rotary packer moves each grid in turn through a discharge station where these groups of articles are dropped into upwardly open packing cases.
Both the infeed and discharge stations of such a continuous motion packer operate without interrupting motion of the articles or movement of the packing case being filled. The disclosure in said pending application is incorporated by reference herein. However, a brief description of the overall rotary packer is included for reference purposes.
The continuous motion bottle packer disclosed in said pending application includes article conveyor means for advancing the articles continuously in side-by-side columns along a first horizontal path. These articles are arranged in end-to-end relationship between lane dividers, and means is provided for forming groups of these articles, corresponding to the capacity of the cases to be packed. Another copending application Ser. No. 565,754 is also incorporated herein and was filed Dec. 27, 1983 and illustrates a preferred means for grouping the articles. Although such grouper means does not comprise an essential element of the present invention and need not be described in detail herein a brief summary is provided for clarity. In its preferred form the grouper includes at least two sets of conveyor means, each of which has flight bars with projecting pins so that the chains can be driven in timed relationship with a pocket chain or lug conveyor to advance the grouped articles through the infeed station. Each chain set is driven at a variable speed so that the projecting pins on each chain set follow distinct a cycles as the chains move the flight bar mounted pins around a closed orbit that includes a common upper run so oriented that all of the pins move in the same path and in the same direction as the advancing articles. Differential means couples one chain set to the other so that the said other chain set and its pins move in the same orbit but at a speed which varies inversely to that of the one chain set and its associated pins. The pins on the flight bars associated with each chain set are preferrably provided in staggered relationship to one another to establish the pitch distance between their associated pins. Means is preferably provided for adjusting the pitch of these pins relative to one another to accommodate predetermined numbers and/or sizes of articles within the article groups.
The infeed station of the rotary packer is provided at the downstream end of the lane conveyors and includes spaced cantilevered fingers for slidably receiving the columns of articles with the fingers being so spaced as to define horizontally extending openings therebetween. A plurality of grid structures are rotatably supported in the packer frame and each grid is adapted to pass upwardly through these finger openings as a result of the unique construction for these grids. Each grid consists of longitudinally extending support rails which carry corner posts defining pockets for the individual articles. Front and rear cross members of each grid structure support the ends of each rail, and the corner posts have upper portions which fit between adjacent articles in the advancing article group as each grid moves upwardly through the infeed station.
The grid structures move in a circular orbit oriented in a vertical plane and the tangential direction of movement for the grid structures entering the infeed station forms an acute angle with the horizontal path of the articles themselves as they arrive at the infeed station. The horizontal component of the tangential velocity vector for the grid structures is such that it matches the horizontal speed of the articles moving into the infeed station. Thus, a slight acceleration of the grid and articles entrained therein is achieved as the grid moves away from the infeed station because the tangential speed of the grid does exceed the linear speed of the articles moving into the infeed station. The infeed station is located near the top of the circular orbit.
Each grid structure includes pivotable vanes for engaging and supporting the undersides of the articles held in the grid, and these vanes also serve to slidably support the articles as they are received in the grid at the infeed station. A smooth transition is thereby provided for the motion of the articles as they are accelerated from the straight line infeed direction to the slightly faster circular orbital speed. Each grid is pivotably supported in the rotating grid support structure so that it remains in a horizontal orientation as it travels around the 180 arc of the circular orbit to a discharge station.
The discharge station is defined at the low point of the orbit, and case conveyor means, to be described, presents upwardly open cases sequentially to the discharge station. Although the copending application referred to above discloses the general concept of driving this case conveyor at a speed which varies cyclically to correspond to the horizontal component of motion for the orbiting grid structures, a problem can be encountered when many (N) grid structures are provided in the rotary packer. Whereas the copending application discloses that it is possible to match the horizontal component of velocity of a single grid moving through the discharge station the present invention seeks to solve the problem of how to accommodate and match the speeds of two adjacent grid structures as they move one after the other in close sequence through such a discharge station.
Slightly ahead of the low point in the orbit the pivoted vanes of each grid are retracted into vertical alignment with the grid rails, and the articles are allowed to free fall into an upwardly open packing case moving in timed relationship with the grid, and located immediately below the grid in the case conveyor system. A funnel structure is preferably provided in each grid for guiding the articles into the packing case and the funnel structure comprises depending fingers which must mate with the case to guide and to control the descending articles as they drop into the case. These fingers of the funnel structure also serve to decelerate the articles as they are so dropped in guided fashion, all without interrupting the motion for the articles and of the packing cases.
The chief aim of the present invention then is to provide an improved system for handling the cases whereby adjacent cases in the line of cases move in the same direction but at a speed which changes instantaneously, one relative to another.